Multi-TeV to PeV Gamma Ray Astronomy

Transcription

1 Multi-TeV to PeV Gamma Ray Astronomy Motivation and Strategies Martin Tluczykont The Future of Research on Cosmic Gamma Rays, La Palma, August 2015

2 VHE-UHE Gamma-ray astronomy

3 Multi-TeV to PeV Gamma rays No hadronic/leptonic ambiguity: IC: Klein-Nishina regime steep spectra Pi decay: hard spectra possible Absorption e+e-: 20+TeV: Mid- to far-infrared region of EBL (Extragalactic) 100 TeV: ISRF (Galactic) 3 PeV: CMB (Galactic) Galactic objects (Moskalenko 2006)

4 Absorption (e + e - ), Galactic MGRO J2031 A. Maurer Topic absorption most interesting for Multifrequency conference! Many Galactic sources: Weak absorption up to 300TeV Universal feature: Distance-dependent absorption above 300TeV

5 Pevatrons Galactic cosmic rays up to knee: Gamma-rays up to few 100 TeV Pevatrons Most energetic particles released first PeV C.R. only for a short period of time Delayed multi-tev signals from clouds Gabici & Aharonian 2007 Use clouds for C.R. acceleration mapping Recent motivation: H.E.S.S. Galactic center, IceCube Neutrinos

6 Key to Multi-TeV PeV : Large area

7 CTA See Friday: Knödelseder, Chaves, Brown

8 HAWC HAWC See wednesday: Sandoval

9 LHAASO HAWC LHAASO See Friday: Simeone

10 HiSCORE HAWC HiSCORE

11 TAIGA 1km² 10km² TAIGA HAWC

12 ASGaRD ASGaRD (7 km²) HAWC ASGaRD

13 Detection methods for gamma astronomy Method E thr Angular resolution ΔE/E γ/h Duty cycle Particles ~3 TeV ~ % ~1 100% Water: 100 GeV < % ~6 Air Cherenkov photons IACTs: 5GeV NonI: 10 TeV % ~6 ~ % Fluoresc. Radio 10¹ ⁷ ev > %? 10% 10¹ ⁷ ev < %? 100%

14 Detection methods for gamma astronomy Method E thr Angular resolution ΔE/E γ/h Duty cycle Particles ~3 TeV ~ % ~1 100% Water: 100 GeV < % ~6 Air Cherenkov photons IACTs: 5GeV NonI: 10 TeV % ~6 ~ % Fluoresc. Radio 10¹ ⁷ ev > %? 10% 10¹ ⁷ ev < %? 100%

15 From HiSCORE to TAIGA

16 The HiSCORE Concept 2014APh T Hampf et al. 2013, NIMA MT et al. ECRS Kiel 2014

17 The HiSCORE Concept 4x 8inch PMTs Winston cones Lightcollection 0.5 m² GHz readout 60 FoV Tilting for extension of sky coverage

18 Tunka-HiSCORE Hamburg Berlin Moscow Irkutsk Tunka Cosmic ray experiment Tunka-133: 1 km² dense array Energy threshold ev Tunka-HiSCORE: 9-station array 25+stations

19 Tunka-HiSCORE Prototype-array (2014): 9 stations, 300m X 300m 2 parallel DAQ systems Energy threshold: <30 TeV 0.5 m² light collection 4 channels (PMT + Cone) Tunka-133 HiSCORE-prototype

20 Angular resolution Crucial: relative time-synchronization <1ns Two time-calibration systems: DRS4 channel used for clock sampling (sent over fiber) WhiteRabbit system (ethernet-based t-cal)

21 Time calibration T-cal systems yield comparable accuraccies (<0.5 ns) White Rabbit in laboratory: <60 ps resolution achievable (PoS ICRC 2015, Wischnewski et al.)

22 Tunka-HiSCORE data vs MC S. Epimakhov, PoS, ICRC 2015

23 Tunka-HiSCORE real data Reconstruct using two different subarrays Split array analysis Subarray 1 Ψ Subarray 2 Tested for 9-station array Resulting resolutions (hadrons): Direction: 0.19 Core position: 4m Energy: 10% PoS, ICRC 2015, Porelli et al. And Epimakhov et al.

24 Particle separation Q-factor (only timing array) Xmax vs. E Shower front rise time Systematic differences between Xmax reconstruction methods

25 Tunka-HiSCORE TAIGA Tunka Advanced Instrument for Gamma ray and cosmic ray physics 10/2014: extension Total: 29 stations Tunka-HiSCORE 2013 Tunka-HiSCORE 2014 Tilting mode 0.25 km² 2015+: First telescope Hybrid timing+imaging In total 10 telescopes planned Muon detectors

26 TAIGA collaboration HiSCORE array + IACTs + Muon detectors

27 Combining a timing array with an imaging telescope

28 Air Cherenkov imaging and timing H.E.S.S. Telescopes Imaging arrays Timing arrays (=non-imaging) MAGIC camera image Past: Themistocle, AIROBICC Today: HiSCORE, TAIGA

29 Air Cherenkov imaging and timing Imaging ACTs Timing arrays Direction Image orientation Shower front arrival times Particle type Image shape Lateral density function Arrival times Time width (FWHM) Energy Ch. photon count Ch. photon count

30 TAIGA Telescopes Dish: Davies-cotton tesselated, 34 mirrors (60cm) 4.3 m dish diameter 4.75 m focal length F/D ~ PMT camera fov 8 (0.38 / pixel) Proven design components Preliminary drawing

31

32 Timing and imaging hybrid detection

33 Telescope image scaling Central reconstruction parameter: Shower core position D K

34 D K D K ~100 m Hybrid imaging + non-imaging Imaging (stereo) 600 m

35 D K D K Hybrid Image scaling: D K from timing array Image from telescope(s) large inter-telescope distance = large A eff! ~100 m scaled width separation parameter Imaging (stereo) Hybrid imaging + non-imaging (+ stereo at high energies, mean scaled width) 600 m

36 HiSCORE + IACTs Preliminary results hybrid width scaling: Separation quality significantly improved Increases total area as compared to stereoscopic array Also see: Kunnas et al. 2015, PoS ICRC 2015 Apply scaled width cut: Q-factor ~2

37 TAIGA 1km² 10km² TAIGA HAWC

38 TAIGA Muon detectors Planned: equip 0.2% of array area with Muon detectors

39 TAIGA Muon detectors Planned for the 1 km² stage: equip 0.2% of array area with Muon detectors 1km² 10km² TAIGA

40 FAMOUS / ASGaRD / LoTOS Similar detector size Introducing Minimal Imaging Shayduk et al. 2015, PoS ICRC 2014

41 FAMOUS / ASGaRD / LoTOS Optical station with minimal imaging Acrylic Fresnel lens 0.3m radius 2000 SiPM camera equipped with light-guides 50 FoV Shayduk et al. 2015, PoS ICRC 2014

42 Summary Different approaches to cover Multi-TeV PeV gamma-ray regime Promising avenue: combine techniques Imaging/timing/(particles) Particles/photons Large arrays possible with low level of complexity Potential for opening up gamma-ray astronomy in the multi-tev regime

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44 Backup slides

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46 Timing of air showers Particle front disk width: 100 m Cherenkov light front: disk width: < m 500 TeV 200 m

47 Galactic Gammas beyond 10 TeV Ackermann et al MGRO J () Tycho (Park et al. 2013)

48 TAIGA HSCW vs. HESS MRSW TAIGA H.E.S.S. Q-factor ~ 2 Q-factor ~ 3

49 Tibet AS-Gamma Argo YBJ LHAASO Tunka-133 Tunka-Rex HAWC Timing arrays PACT Tunka-HiSCORE HAGAR STACEE IceCube

50 Gamma-ray astronomy Milkyway

51 Timing Reconstruction Tunka-133 [Berezhnev et al. 2012NIMPA B] HiSCORE [Hampf et al. 2013NIMPA H] HiSCORE event display 500 TeV gamma-ray Simulation

52 Timing Reconstruction Tunka-133 [Berezhnev et al. 2012NIMPA B] HiSCORE [Hampf et al. 2013NIMPA H] Shower core position 1 (cog) Preliminary direction (time plane fit) Improved core position: light distribution function (LDF) fitting Improved direction: arrival time model Fit of signal time widths

53 Arrival time model 2013NIMPA H

54 Arrival time model r: Distance from shower core to detector Shower height in km Slope of atmospheric refractive index Zenith angle

55 Time calibration

56 Energy determination Energy light density Q(x) = LDF at x m 2012NIMPA B

57 Energy determination HiSCORE simulation

58 Shower maximum Time model method: X max free parameter in arrival time model LDF method: X max from LDF slope, Q50/Q220 Width method: X max from signal width Xmax Xmax D. Hampf, MT, D. Horns, NIMA 2013 Prosin, ECRS 2010

59 HiSCORE Simulation Shower maximum

60 Particle separation Xmax vs. E

61 Gamma-hadron separation Systematic bias LDF & widths : sensitive to whole shower Large overestimation for heavy particles (long tails) Timing : sensitive to specific point (edge time) Small overestimation for heavy particles

62 Particle separation Lighter particles develop Higher up in atmosphere

63 Particle separation (2) Systematic Xmax difference Time width and timing model

64 Particle separation timing Systematic difference Cherenkov signal rise times

65 Sky coverage Standard observation mode: station points to zenith Tilted mode: inclined along the north-south axis. Tilting: coverage of different parts of the sky. N Tilted south mode: 110 h on the Crab Nebula, after weather corrections. Normal mode Tilted south 30 mode

66 Past experiments Themistocle AIROBICC

67 AIROBICC results

68 Hybrid events: more reconstruction Expect sensitivity boost: Scaled width cut and timing hadron rejection (Q~3) Further g/h separation: Angular cut, length, (+ more sophisticated methods) Improved angular resolution from hybrid events: e.g. treat telescope as part of array (not yet simulated) Consider time-development of image independent direction reconstruction

69 Large zenith angle: outside HiSCORE viewcone gradient sim_telarray simulation, 2010 Core distance

70 Test width scaling with IACT+HiSCORE toy-mc-test Full simulation sim_telarray 2D-lookup-table for MC-width wmc (core, size) MC-core randomized with HiSCORE resolution Use randomized core position for width scaling

71 Optical station Tunka HiSCORE Status Electronic box

72 Array Optimization HiSCORE Simulation studies: Large PMTs (12'') Graded array layout

73 HiSCORE + IACTs sim_telarray

74 Timing array + imaging telescopes Central reconstruction parameter: Shower core position IACT image scaling using array core position Monoscopic operation with larger distances btw telescopes (also see Kunnas et al., this conference) Increased area / telescope; Hybrid event reconstruction improvement of g/h separation x2-3

75 Milagro / HAWC HAWC

76 MGRO J Assuming pevatron with cutoff at 3PeV HiSCORE 10 km² No IACT µ det. 1 year (200h)

77 Tycho Supernova remnant Assuming pevatron with cutoff at 3PeV HiSCORE 100 km² No IACT / µ det. 3 years

78 Absorption Galaxy: 100TeV-PeV: e+e-pair production with low-e photons Interstellar radiation field Cosmic Microwave Background (e.g. Moskalenko et al. 2006)

79 Particle separation Xmax vs. E